The invention relates to a directional and warning blink apparatus for a vehicle, in particular a motor vehicle, comprising two groups of blink signal lamps, a directional blink switch for selecting a blink signal lamp group, a warning blink switch for combined switching of both blink signal lamp groups, a directional warning blink sender including a relay for controlling the blink signal lamps, a timing generator for producing timing signals, a driving circuit for controlling the relay as a function of the timing signals of the timing generator, and a control and logic circuit having a measuring input terminal to which is applied a voltage signal proportionate to a blink signal lamp current and controlling the timing operation of the timing generator depending upon the voltage signal.
Such an apparatus serves for intermittently controlling one or several blink signal lamps, in particular for indicating direction and emitting warning signals. Construction of such an apparatus is determined in particular by the two executed functions, described in the following as "operational modes". These modes are distinct from one another, in particular in the load proportions they place on the directional warning blink sender. Generally, in the directional-blinking operational mode, only a portion of the existing blink signal lamps are driven at a time, since the elected portion, in particular, provides certain information, for example, about the elected direction. In the warning-blinking operational mode, on the other hand, preferably all blink signal lamps are driven in order to make warning blink signals as distinct as possible in addition to making them clearly distinguishable from directional blink signals.
Further demands on the directional and warning blink apparatus, in regard to the different operational modes, result from situations in which these operational modes are used. The directional and warning blink apparatus is used in particular in the warning-blinking operational mode when a car breaks down or after an accident. Particularly after an accident, it is improbable that all blink signal lamps are still functioning. It is an object that the warning blink signal be produced by the remaining functioning blink signal lamps as unvaried as possible. The directional blink signal, on the other hand, is used in normal driving situations and serves to inform other traffic participants about intentions of a vehicle driver. Without this information, in particular due to defective blink signal lamps, accident-prone situations may result. The driver of a vehicle must, therefore, be informed about non-functioning of blink signal lamps. Normally, this is achieved by changing the blink frequency of remaining functioning blink signal lamps, particularly by increasing blink frequency.
In summary, this has led to a requirement that, in the directional-blinking operational mode, failure of only one (preferably) blink signal lamp results in a change in blink signal frequency, while in the warning-blinking operational mode the blink signal frequency remains constant up to a minimal number of functioning blink signal lamps. This specification has become law in some countries, in particular in the United States. According to US requirement, or standard, MVSS 108, blinking in a warning-blinking operational mode must be executed at normal blinking frequencies with two or more functioning blink signal lamps, while in a directional-blinking operational mode, normally a failure of only one blink signal lamp requires an increasing blink signal frequency.
In the US, standard directional and warning blink apparatus have two, three or four blink signal lamps per vehicle side. In an embodiment of the blink apparatus with three blink signal lamps per vehicle side, the above mentioned requirements result in the following problem:
While the directional and warning blink apparatus must indicate failure of one blink signal lamp (that is, reduction from three to two functioning blink signal lamps) by increasing the blink signal frequency in the directional-blinking operational mode, blinking in the warning-blinking operational mode must be executed at normal frequencies, if there are still two functioning blink signal lamps. A similar problem exists for directional and warning blink apparatus with four blink signal lamps per vehicle side when only three or two blink signal lamps are functioning.
Only in Europe does this problem not arise in standard motor vehicles with two blink signal lamps per vehicle side, since in both the warning-blinking and directional-blinking operational mode the blink signal frequency is increased when only one functioning blink signal lamp remains.
German patent document DE-AS 2 153 375 depicts a particularly uncomplicatedly constructed directional and warning blink apparatus. The directional warning blink sender herein is constructed in a two-pole embodiment. The blink signal lamp current timed by the directional warning blink sender is distributed to two blink signal lamp groups with two blink signal lamps each via a directional blink switch and a warning blink switch. If the blink signal frequency of such a directional warning blink sender is constructed to be load-controlled such that, for example, the directional and warning blink apparatus blinks faster with only one controlled directional warning blink signal lamp than with two or more driven blink signal lamps, such an apparatus would fulfill the requirements for a directional and warning blink apparatus with two blink signal lamps per vehicle side. For directional and warning blink apparatus with three or four blink signal lamps per vehicle side the above mentioned requirements certainly cannot be met by such an apparatus, because the directional warning blink sender must receive information about the predetermined operational mode for certain numbers of driven blink signal lamps in order to drive the blink signal lamps at a correct frequency.
Directional and warning blink apparatus comprising several blink senders for executing certain functions have been known for a long time, for example, from prior-art U.S. Pat. No. 3,165,716. Such an apparatus can, for example, be constructed such that it comprises separate warning blink and directional blink senders. These individual blink senders can certainly be constructed such that they fulfill all requirements for the respective operational mode. Such a solution requires very little constructional effort, since a special apparatus is provided for each operational mode which is easily adaptable to any requirements. On the other hand, this solution requires numerous components, therefore being very cost-intensive, since both the directional blink sender and the warning blink sender need individual housings as well as separate driving electronics and individual relays for a minimum requirement. Further, due to little available space in motor vehicles, it may be difficult to find appropriate mounting space for separate directional warning blink senders. Installing one housing for both apparatus is only a partial solution for these problems. The expense for one large housing as compared to that for two smaller ones may be somewhat lower, however, expenses for components and space requirements for mounting the apparatus remain almost unchanged.
A combined directional and warning blink apparatus without the above mentioned disadvantages is available in the directional warning blink sender, type 4DD 006 321-01, as exported to the US since May 1989 by Hella KG Hueck & Co.
Such a directional and warning blink apparatus is depicted schematically in FIG. 6 hereof and will be explained in detail concerning its construction and functions. In this device a single relay controls the blink signal lamps in both operational modes. Therefore, only one blink sender electronic package is required comprising a control and logic circuit, a timing generator and a driving circuit for the relay. It is beneficial that the above mentioned elements are arranged in an integrated circuit having a measuring input terminal on to the control and logic circuit, to which is applied a potential depending upon a blink lamp current. This potential is increased in case of failure of one or several blink signal lamps, thereby enabling the control and logic circuit to recognize such failure, thus causing the timing generator to change its timing operation, for example, by increasing timing frequency.
If it is predetermined by means of the directional and warning blink switches for the operational mode to be warning blinking, the potential at the measuring input terminal is lowered via an additional switch contact of the directional warning blink switch and via a resistor so that the potential stays below a certain threshold value even in case of failure of blink signal lamps, thereby preventing the control and logic circuit from recognizing such failure. In the warning-blinking operational mode, the remaining functioning blink signal lamps are, therefore, driven with normal timing frequency even after failure of one or several blink signal lamps.
This directional and warning blink apparatus thus meets US acceptance requirements in an uncomplicated and cost-effective manner.
The only disadvantage of this directional and warning blink apparatus is that the design layout of the directional and warning blink apparatus almost completely predetermines its external circuits, in particular the number of contacts of its direction and warning blink switch.
The external wiring of directional and warning blink apparatus in motor vehicles are, however, not standardized. They differ, in particular, in the kind and number of switch contacts of the directional and warning blink switch as well as their circuit arrangements with the remaining elements of the directional and warning blink apparatus. The use of the above described directional warning blink senders is, therefore, not possible in all motor vehicles, unless cost- and time-intensive modifications in the electrical arrangement of the motor vehicle are done. In particular in series manufacturing, cost-intensive modifications of pre-molded wiring harnesses may become necessary, wherein the use of such a directional warning blink sender, although generally beneficial, causes additional expenses and often is not used for this reason.
It is an object of this invention to provide a directional and warning blink apparatus having a directional warning blink sender which can be constructed cost-effectively and is easily adaptable to multiple kinds of external wirings.